HD 170657
From Infogalactic: the planetary knowledge core
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Sagittarius |
| Right ascension | 18h 31m 18.9597s[1] |
| Declination | –18° 54′ 31.722″[1] |
| Apparent magnitude (V) | 6.82 |
| Characteristics | |
| Spectral type | K2V[2] |
| U−B color index | +0.56[3] |
| B−V color index | +0.87[3] |
| Variable type | Suspected[4] |
| Astrometry | |
| Radial velocity (Rv) | –35[5] km/s |
| Proper motion (μ) | RA: –140.14[1] mas/yr Dec.: –194.60[1] mas/yr |
| Parallax (π) | 75.71 ± 0.89[1] mas |
| Distance | 43.1 ± 0.5 ly (13.2 ± 0.2 pc) |
| Details | |
| Mass | 0.79 ± 0.11[6] M☉ |
| Surface gravity (log g) | 4.61[6] cgs |
| Temperature | 5,156[6][7] K |
| Rotational velocity (v sin i) | 1.5[6] km/s |
| Age | 1.6–6.1[7] Gyr |
| Other designations | |
HD 170657 is a star in the constellation Sagittarius. It is located at a distance of about 43 light years. It has 0.79 solar masses and is a suspected variable star that varies in apparent magnitude from 6.82−6.88.[4]
When observed with the Spitzer Space Telescope, this star did not display an excess emission of infrared radiation, which may otherwise indicate the presence of an orbiting debris disk.[7] The space velocity components of this star are (U, V, W) = (–41, –26, +6) km/s.[9]
Sources give contradictory measurements for the abundance of elements in this star. Lawler et al. (2009) lists an iron abundance of [Fe/H] = 0.27 dex,[7] while Valenti et al. (2005) has an iron abundance of [Fe/H] = –0.15.[6]
References
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